In multistage pumps for pumping well fluid from oil and water wells, it is common practice to interpose thrust washers to support rotating impellers and to absorb thrust loads experienced during pumping. Lubrication for these thrust washers is provided by the fluid being pumped, which, at times, may contain abrasive particles, such as sand. Generally these thrust washers are received in an annular groove or retaining ring portion of the impeller closely adjacent to an annular skirt portion of the impeller. Preferably the thrust washers are inserted in the grooves with a slight interference fit; but because of manufacturing tolerances, this is not always the case. Thus, at times, thrust washers because of their size and because they are placed between a stationary part (a diffuser) and a rotating part (an impeller) tend to spin or rotate at speeds less from that of the impellers. When used in abrasive fluids, as when there are sand particles present, the difference in rotational speeds of the washers and the impellers causes excessive wear that at times is so severe as to damage one or more of the skirt portions of the impeller.
Attempts to retain these thrust washers by glueing, cementing, and staking the washers in position, or by peening and crimping various parts of the impeller have not been successful nor economically feasible.